A casualty is the damage, destruction, or loss of property resulting from an identifiable event that is sudden, unexpected, or unusual. 1  A sudden event is one that is swift, not gradual or progressive. 2  An unexpected event is one that is ordinarily unanticipated and unintended.
exists and is an alternate of . The noble gas notation is a notation formed as a result of the electron configuration notation being used in conjunction with noble gases. The noble gas preceding the element in question is written then the electron configuration is continued from that point onwards. The notation is shorter to write and makes it easier to identify elements.
At the top of the noble gases is little helium (He), with a shell that is full with only two electrons. The fact that their outer shells are full means they are quite happy and don't need to react with other elements. In fact, they rarely combine with other elements. That non-reactivity is why they are called inert. All of the elements in Group Zero are noble gases. The list includes helium, neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Don't think that, because these elements don't like to react, we don't use them. You will find noble gases all over our world.